As the development of technology, conventional fluorescent lamps are gradually replaced by LEDs (light emitting diodes) in applications such as LCD backlighting and lighting. In the application of smart LED lighting, a driver is needed to provide a controllable current. Different power supply voltages, such as 3.3V, 5V etc. are also needed to power smart modules (e.g. microcontroller unit (MCU), wireless module R/F, etc.) at different situations.
Conventional two-channel LED drivers typically adopt two power stages: a first stage including a converter (e.g. a flyback converter) to provide two constant voltages, with one voltage used to drive the LEDs, and the other voltage used to power other modules; and a second stage including two step-down converters, to control the current flowing through the LEDs in the two channels, respectively.
However, such two-channel LED driver with two power stages has complicated circuit structure, large volume and high cost.